[gdal-dev] using gdalwarp with a new projection in proj.4

[Frank Warmerdam]

Michael,

Healpix is not directly supported by OGRSpatialReference - the core of the
coordinate system machinery for GDAL/OGR.  However, you can request GDAL to
treat this as a PROJ.4 extension to WKT by adding the +wktext flag.  I
would add that the -E and -f flags are options to the cs2cs commandline
program, and not part of a PROJ.4 coordinate system and so should not be
included.  The result is something like this:

gdalsrsinfo '+proj=rhealpix -I +lon_0=0 +a=1 +ellps=WGS84 +npole=0 +spole=0
+wktext'

PROJ.4 : '+proj=rhealpix -I +lon_0=0 +a=1 +ellps=WGS84 +npole=0 +spole=0
+wktext'

OGC WKT :
PROJCS["unnamed",
    GEOGCS["WGS 84",
        DATUM["unknown",
            SPHEROID["WGS84",6378137,298.257223563]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["custom_proj4"],
    EXTENSION["PROJ4","+proj=rhealpix -I +lon_0=0 +a=1 +ellps=WGS84
+npole=0 +spole=0 +wktext"]]

Best regards,
Frank



On Tue, Jul 16, 2013 at 6:48 PM, Michael Speth <
spethm at landcareresearch.co.nz> wrote:

>  Greetings,
>   I am unable to use the HEALpix and rHEALPix projections which have been
> added about a year ago to proj.4 in gdalwarp.  Is there a configuration
> file for gdal that needs to be updated for this projection?
>
>  Here is the command in question that fails:
>
> gdalwarp -s_srs EPSG:26711 -t_srs '+proj=rhealpix -f '%.2f' -I +lon_0=0
> +a=1 +ellps=WGS84 +npole=0 +spole=0 -E'  ~/data/utm_orig.tif rhealpix.tif
> The error message
> “Translating source or target SRS failed:”
>
>  Thanks
> --
>
> Michael Speth
> Research Systems Developer
> Landcare Research
>
>
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-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Software Developer
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